The present invention is an improvement over structure disclosed in U.S. Pat. No. 4,214,495. As shown in FIG. 8 of said patent, web guides are provided for guiding the web. The apparatus in said patent is arranged to automatically slit and score a web. On occasion it is desired to process mill run board, that is board which is not scored. Mill run board is trimmed at its side edges to a desired width.
When mill run board is being processed, and has a substantial width, the board tends to bow downwardly in its center due to its weight. When the mill run board leaves the slitter, it will be trimmed to a width which is greater than that desired. The present invention is directed to recognition of the problem with a solution based on using already existing components to perform an additional function.